This invention relates generally to prefabricated foundation footings for constructing buildings and more specifically to a particular prefabricated footing/pier and a system and method for using it.
It has long been recognized that houses, utility buildings and other structures should be erected upon a foundation rather than simply being placed directly on the earth, and most such foundations are made of poured concrete footings with a wall or piers of hollow concrete blocks set in place thereon. This kind of foundation is now standard in the building industry.
Typically, such foundations are constructed by first laying out the parameters of a foundation wall with batter boards, grade stakes, nails and string. Then a crawl space area is excavated, and continuous footing trenches are dug, leveled, and tamped. Reinforcing rods or elements are then placed in the trenches, and concrete is poured and allowed to set to form a footing for receiving the hollow concrete blocks.
The concrete blocks are then set by hand upon the poured footings, one at a time, using cement mortor as the leveling and bonding medium. Finally, the building is installed on a series of concrete block piers and is secured thereto by anyone of several methods. This process for foundation construction is labor intensive and calls for a number of different skills by the workmen. It is also subject to a number of construction errors, such as can occur when foreign materials, like pieces of wood, are utilized to initially support the reinforcing elements, and are then not removed before pouring the concrete.
There are, in fact, a number of disadvantages with this kind of foundation construction, including the following:
1. structural quality of a poured continuous footing is difficult to control on the job site because of failure to properly install reinforcement elements, earthen footing trench walls caving in before or during placement of the concrete and weather conditions such as heavy rains occuring before the concrete has been poured and sets. These conditions usually result in later differential settlement of the footings at points where their structural integrity is impaired, which can cause resultant damage to the concrete block piers and to the building structure resting on the footings. In the case of the block piers, the resulting damage can be in the form of continuous cracks in mortor joints or even ultimate block failure if the weight of the building is shifted and becomes improperly applied. The building itself can be damaged to a lesser or greater extent, ranging from wall cracks and non-alinged doors and windows to collapse of the whole building.
2. Because of the complexity of the construction, poured in placed footing and hollow concrete block foundations require careful coordination between a number of different workmen's skills, which skills may or may not always be available and, the practice of which in all cases requires many hours of increasingly expensive labor.
3. The construction of poured in placed footing and hollow concrete block foundations is especially dependent upon relatively lengthly periods of good weather, because of the time required for construction and the use of earth and trenches for the footings.
All of these disadvantages are heightened when working with the modular or prefabricated buildings of today, which arrive at a job site ready to be installed in functioning condition. The transport of these manufactured buildings is expensive and must be properly scheduled to achieve economically satisfactory results, but this scheduling is difficult to achieve in many instances because of the unanticipated delays often involved with normally poured footing and concrete block type foundations.
The need for better foundation construction methods has been recognized, and there have been attempts to provide improved foundations. One such effort is represented by U.S. Pat. No. 4,107,889, wherein precast concrete beams are installed upon poured-in-place piers utilizing hollow pedestals, reinforcement elements, and poured concrete for the actual installation. However, the basic problems with pouring concrete into earthen forms is present, and the workmen's skills required for construction are still extensive and the process lengthy.
U.S. Pat. No. 4,275,538 to Bounds describes a building foundation method and systems which include preformed footings and cast concrete beams which span the footings for supporting a building. However, the precast footings are somewhat unwieldy to grip and put into place, and their incorporation into a system is unduly complicated. Further, Bounds method is somewhat labor intensive in that it involves the hand digging of footing cavities, the pouring of concrete, and a number of other time consuming tasks.
There is, thus, still a need for improved prefabricated foundation elements and a method and system for use thereof to reduce the type and amount of skilled labor needed at a job site and which will produce significantly superior foundations of uniformly high quality at a lower cost than has been previously possible. It is an object of this invention to provide such prefabricated foundation elements and a method and system for using the same.
It is a further object of this invention to provide a prefabricated foundation element which provides both a foundaton footing and a pier but yet which is easy to transport, handle, and install for creating a foundation system.
It is also an object of this invention to provide a prefabricated foundation element which is inexpensive to both manufacture and to use.